To provide novel low-temperature sinterable copper particles that can be sintered even at a low temperature of, for example, around 100° C. or less, and a method for producing a sintered body by using the same. The low-temperature sinterable copper particles according to the present invention are coated with a carboxylic acid, and a surface of the copper particle is oxidized so as to have a cuprous oxide fraction (Cu.sub.2O/(Cu+Cu.sub.2O)) in the copper particle of 4% by mass or less or so as to have an average coating thickness of cuprous oxide of 10 nm or less. The low-temperature sinterable copper particles are subjected to low-temperature firing in an atmosphere of 0.01 Pa or less.

An example of a three-dimensional (3D) printing kit includes a build material composition and a fusing agent to be applied to at least a portion of the build material composition during 3D printing. The build material composition includes a polyamide having a melt enthalpy ranging from greater than 5 J/g to less than 150 J/g. The fusing agent includes an energy absorber to absorb electromagnetic radiation to coalesce the polyamide in the at least the portion. The fusing agent is a core fusing agent and the energy absorber has absorption at least at wavelengths ranging from 400 nm to 780 nm; or the fusing agent is a primer fusing agent and the energy absorber is a plasmonic resonance absorber having absorption at wavelengths ranging from 800 nm to 4000 nm and having transparency at wavelengths ranging from 400 nm to 780 nm.

An example of a three-dimensional (3D) printing kit includes a build material composition and a fusing agent to be applied to at least a portion of the build material composition during 3D printing. The build material composition includes a polyamide having a melt enthalpy ranging from greater than 5 J/g to less than 150 J/g. The fusing agent includes an energy absorber to absorb electromagnetic radiation to coalesce the polyamide in the at least the portion. The fusing agent is a core fusing agent and the energy absorber has absorption at least at wavelengths ranging from 400 nm to 780 nm; or the fusing agent is a primer fusing agent and the energy absorber is a plasmonic resonance absorber having absorption at wavelengths ranging from 800 nm to 4000 nm and having transparency at wavelengths ranging from 400 nm to 780 nm.

A copper-based ink contains copper hydroxide and diethanolamine. The ink may be coated on a substrate and decomposed on the substrate to form a conductive copper coating on the substrate. The ink is low cost and micron-thick traces of the ink may be screen printed and thermally sintered in the presence of up to about 500 ppm of oxygen or photo-sintered in air to produce highly conductive copper features. Sintered copper traces produced from the ink have improved air stability compared to traces produced from other copper inks. Sintered copper traces having sheet resistivity of about 20 mΩ/□/mil or less may be obtained for 5-20 mil wide screen-printed lines with excellent resolution.

A copper-based ink contains copper hydroxide and diethanolamine. The ink may be coated on a substrate and decomposed on the substrate to form a conductive copper coating on the substrate. The ink is low cost and micron-thick traces of the ink may be screen printed and thermally sintered in the presence of up to about 500 ppm of oxygen or photo-sintered in air to produce highly conductive copper features. Sintered copper traces produced from the ink have improved air stability compared to traces produced from other copper inks. Sintered copper traces having sheet resistivity of about 20 mΩ/□/mil or less may be obtained for 5-20 mil wide screen-printed lines with excellent resolution.

Water-based nanoparticle inks may be formulated to be compatible with printed electronic direct-write methods. The water-based nanoparticle inks may include a functional material (nanoparticle) in combination with an appropriate solvent system. A method may include dispersing nanoparticles in a solvent and printing a circuit in an aerosol jet process or plasma jet process.

Water-based nanoparticle inks may be formulated to be compatible with printed electronic direct-write methods. The water-based nanoparticle inks may include a functional material (nanoparticle) in combination with an appropriate solvent system. A method may include dispersing nanoparticles in a solvent and printing a circuit in an aerosol jet process or plasma jet process.

A ink-jet ink composition according to the present disclosure contains a colorant, water, a 1,2-alkanediol, and a water-soluble 1,3-dioxolane compound represented by the following formula: ##STR00001##
where R.sup.1 and R.sup.2 are independently selected from linear or branched alkyl groups containing one to four carbon atoms and R.sup.3 is a hydrogen atom or at least one selected from the group consisting of an ethylene oxide adduct, a propylene oxide adduct, and a butylene oxide adduct and is terminated with a hydrogen atom.

A ink-jet ink composition according to the present disclosure contains a colorant, water, a 1,2-alkanediol, and a water-soluble 1,3-dioxolane compound represented by the following formula: ##STR00001##
where R.sup.1 and R.sup.2 are independently selected from linear or branched alkyl groups containing one to four carbon atoms and R.sup.3 is a hydrogen atom or at least one selected from the group consisting of an ethylene oxide adduct, a propylene oxide adduct, and a butylene oxide adduct and is terminated with a hydrogen atom.

Carbon nanotube (CNT) ink includes a CNT, a rheological modifier for controlling a flow of the CNT, and a solvent. The CNT ink exhibits a liquid-like behavior under shear stress of 10.sup.−1 to 10 Pa. A loss modulus of the CNT ink may have a larger value than that of storage modulus under shear stress of 10.sup.−1 to 10 Pa. A content of the CNT may be 1 to 20 wt %. A content of the rheological modifier in the CNT ink may be 5 to 40 wt %. A weight ratio of the content of the CNT and the content of the rheological modifier in the CNT ink may be 1:1 to 1:5. The solvent may have a boiling point of 100° C. or less.